EU sure about that hat, your majesty?

A combination of pictures shows Queen Elizabeth during the State Opening of Parliament in central London June 21, 2017 and a European Union flag.Stefan Rousseau/Pool

LONDON (Reuters) - Coincidence or a subliminal message? Britain's Queen Elizabeth stirred up social media on Wednesday when she opened parliament in a hat looking very much like a European Union flag.

Delivering a formal speech in which Prime Minister Theresa May's government laid out its strategy for exiting the EU, the monarch sported a blue chapeau decorated with an arc of blue flowers each with a bright yellow disc at its centre.

It was all a bit Brussels and Strasbourg, where the EU flag -- a blue ensign with a circle of yellow stars on it -- holds pride of place,

Queen Elizabeth smiles as she arrives to attend the State Opening of Parliament in central London, Britain June 21, 2017.Adrian Dennis/Pool

Others on Twitter created composite pictures, with one half showing Elizabeth wearing the hat, the other showing the flag.

Some thought it might have been deliberate on the queen's part. "A bit like her insisting on driving the Saudi king! Subtle royal politics," Simon Hix, political science professor at London School of Economics tweeted.

As head of state, the British monarch refrains from taking public positions on political issues.

A headline published in British tabloid The Sun last year claiming that the queen "backed Brexit", prompted official denials and a complaint to press regulators, which ruled that it was significantly misleading.